Apparatus for connecting together at least two compressors used in refrigeration or air conditioning systems

ABSTRACT

Apparatus for connecting together at least two compressors ( 17 ) used in refrigeration or air conditioning systems, which apparatus comprises a suction header ( 16 ), a discharge header, an oil header, oil return lines and an oil reservoir, which apparatus is such that the suction header ( 16 ), the discharge header, the oil header, the oil return lines and the oil reservoir are connected together in at least one main body component ( 31 ), and which apparatus is such that the compressors ( 17 ) are connected to the main body component ( 31 ) during use of the apparatus.

This invention relates to multi-compressor installations commonly usedin refrigeration or air conditioning systems. More especially, thisinvention relates to apparatus for connecting together at least twocompressors used in refrigeration or air conditioning systems.

Known installations where more than one compressor is used are connectedtogether using pipe systems for suction, discharge and oil pathways. Thepipe systems are typically made from sections of high grade copper orsteel, with standard fittings, valves and all other items connected, forexample by braising, welding or other means.

Pipe sizes are chosen to be as small as possible in order to minimise onthe cost of parts, and also to maximise on the resistance to highpressure or over pressure situations. Narrow pipe diameters cause highgas velocities, which increases losses and creates noise. The known pipesystems are complicated and time consuming to make. In addition, theyrequire the use of skilled labour. Because of the large number ofconnections, there is an increased risk of leakage from the pipesystems. Complex designs inevitably result in high maintenance costs inorder to ensure that pressure integrity is maintained. Often repairs orup-grades on site can only be carried out by skilled workers. In manycases, an official permit is required to work on the apparatus whilst itis in use. All of this increases time and cost.

It is an aim of the present invention to eliminate or mitigate the abovementioned problems.

Accordingly, in one non-limiting embodiment of the present invention,there is provided apparatus for connecting together at least twocompressors used in refrigeration or air conditioning systems, whichapparatus comprises a suction header, a discharge header, an oil header,oil return lines and an oil reservoir, which apparatus is such that thesuction header, the discharge header, the oil header, the oil returnlines and the oil reservoir are connected together in at least one mainbody component, and which apparatus is such that the compressors areconnected to the main body component during use of the apparatus.

The apparatus of the present invention enables improvements to thedesign of multi-compressor installations, with the multi-compressorinstallations afforded by the present invention being simpler and easierto build.

As indicated above, the apparatus of the present invention isconstructed from at least one main body component to which thecompressors are attached. The main body component may be manufacturedwith an internal chamber, ports, valve cavities and other featuresnormally required. The main body component can be manufactured invarious ways, for example by casting.

The apparatus of the present invention may be modular in function,allowing for the very rapid construction of multiple compressor systems,for example utilising two-six compressors without the need for welded orbraised joints. The apparatus so constructed is able to have a largeoverall reduction in the number of joints compared to known pipe worksystem. The apparatus of the present invention enables high numbers ofcompressors to be connected together, this being due to the modularnature of the apparatus.

The apparatus of the present invention may be constructed in modularsections to be fully expandable in order to cope with a variety ofsystem configurations. The apparatus does not need to be braised orwelded as occurs with traditional systems. This means that on-siteupgrades are realistic and practical possibilities. The apparatus of thepresent invention allows for simplified field modifications, andupgrades that do not require skilled welders and official permits, asare required for the above mentioned known systems. In addition, themain body component or components used in the apparatus of the presentinvention can be recycled, and so have an increased life cycle.

The apparatus of the present invention may be constructed to highlysimplified designs that obviate the need for many parts used in knownsystem. These parts used in known systems can be designed out of theapparatus of the present invention, or their function can beincorporated in the apparatus. Using such techniques, individual partsrequired can be drastically reduced, and joints can be reduced by asmuch as 70% compared with known systems.

Because of the low number of joints, and the fact that the joints can bemade without using specialist techniques, the risk of leaks is reduced.

The apparatus may be manufactured from corrosion-resistant materialssuch for example as aluminium. The apparatus is preferably manufacturedby casting but other manufacturing methods may be employed.

The apparatus of the present invention may incorporate a dischargeheader in one main body component suitable for a number of compressors.Additional compressors may be accommodated by attaching at least oneother main body component, for example via a single joint. By thismethod, multiple compressor discharge headers may rapidly be created,using very few joints compared with traditional systems.

The suction header and/or the oil header may be incorporated in the samemain body component as the discharge header, or they may have their ownmain body components which are designed for modular assembly. Theapparatus provides for a wide variety of different combinations ofsuction, discharge and oil headers. Where non-useful heat could takeplace, this may be minimised in the apparatus of the present inventionby the provision of ribs and chambers for providing insulation and/orseparation between two regions of differing temperature.

The oil reservoir function in the apparatus of the present invention isable to be met without the need for a discrete oil reservoir. Increasedchamber sizes in the main body component or components enable enough oilto be held in the apparatus in order to ensure that oil requirements arealways met.

The apparatus of the present invention may include housings for allrequired service, shut-off control and regulating valves in suction,discharge and oil pathways.

The apparatus may include a plurality of gauge and pressure reliefpoints.

The apparatus may be one in which internal cavity sizes aresignificantly larger than in known systems, thereby causing a reducedpressure drop between inlet and outlet sections of the apparatus. Thereduced pressure drop itself may result in a reduced gas velocity thatin turn leads to increased efficiency, and lower gas noise andvibration. Because of this, the apparatus is able to deliver improvedcompressor and system durability, together with energy savings due tothe improved efficiency.

The apparatus may include suction accumulator functionality.

The apparatus may include an oil drain port and an oil sight glass.

As indicated above, the apparatus may be one which is in modular formfor connecting the compressors together by extension modules.

The apparatus may be one in which the oil reservoir is located atcompressor sump level. This enables the cross-sectional area of the oilheader to be maximised, thereby reducing the effect of oil levelfluctuations.

The apparatus may include a detachable oil separator.

The apparatus may be one in which sufficient internal volume and flowarea are provided so that gas balancing of more than three largecompressors is possible in order to ensure consistent oil feed to eachcompressor without the need for an oil-regulating system. Suchcompressors may typically have a capacity of more than 100 m³/hour.

The apparatus may include a bolt-on oil-feeder connector. Alternatively,the apparatus may be one in which oil feed and gas-balancing is combinedin one cavity.

The apparatus may include a bolt-on suction filter assembly, the bolt-onsuction filter assembly incorporating bypass valves and service valves.

The apparatus of the invention may include liquid sub-cooling means.

The apparatus may include a bolt-on oil separator, the bolt-on separatorbeing such that it is cast complete with integral bypass or check valvesand service valves.

An embodiment of the invention will now be described solely by way ofexample and with reference to the accompanying drawings in which:

FIG. 1 is a functional schematic of apparatus of the present inventionfor connecting together at least two compressors used in refrigerationor air conditioning systems;

FIG. 2 shows a schematic layout of the components required in theapparatus shown in FIG. 1;

FIG. 3 is comparable to FIG. 1 and shows known apparatus that would berequired to achieve what is achievable by the apparatus shown in FIG. 1;and

FIG. 4 is comparable to FIG. 2 and shows the components required in theapparatus shown in FIG. 3.

Referring to FIG. 1, there is shown apparatus for connecting together atleast two compressors used in refrigeration or air conditioning systems.The apparatus comprises a number of compressors 1 linked to each otherand to various main body components by refrigerant pathways 2 and oilpathways 3. These pathways 2, 3 are provided in the main bodycomponents. The main body components are linked together via flangedjoints 4. In the main body components, the function of shut-off valves5, non-return valves 6 and pressure tappings/bleed points 7 areprovided. The apparatus is also provided with sight glasses 8. A suctionaccumulator 9 is provided for each compressor 1, this being superior toproviding one suction accumulator 9 for the entire apparatus.

The apparatus shown in FIG. 1 also shows an oil separator 10, a suctionfilter/dryer 11, and end caps/blocks 12. T-joints 13 and bends 14 arealso provided as shown.

The apparatus shown in FIG. 1 does not require a discrete oil reservoir,since there is sufficient oil volume provided in the oil pathways of theapparatus.

Referring now to FIG. 2, there is shown in FIG. 2 by a dashed line 15the functional circuit of FIG. 1. FIG. 2 shows by bold lines requiredphysical main body components that are required by the apparatus of thepresent invention, there is provided a number of main body componentsincorporating several of the functions typically performed by severaldiscrete components in a known conventional system. As can be seen fromFIG. 2, compressors 17 are connected to a suction header assembly 16,that incorporates the function of a suction accumulator 18 and a serviceshut-off valve 19. Provision for further numbers of compressors is madeby modular extension main body components that provide the requirefunctions. A suction header extension 20 is shown to provide the suctionaccumulator 18 and the service valve 19 function in an identical fashionto the suction header assembly 16.

In FIG. 2, it will be seen that there is also provided a combined oiland gas-balance cavity, connected to the compressor via an oil-adapterarm 21. One shut-off valve 22 per oil-adapter arm 21 operates toshut-off gas balancing lines 23 and oil feed lines 24 to the compressor.Each oil-adapter arm 21 also incorporates a sight glass 25. For eachcompressor, there is provided a discharge adapter 26, incorporating anon-return valve 27. The apparatus of the present invention makes itpossible to isolate and service this non-return valve 27, which wouldrequire additional valves in a known conventional system.

An oil adapter 21 and a discharge adapter 26 each connect to adistribution arm 28 that provides for all of the required internalcavities, and provides a discharge shut-off valve 29 and an oil/gasbalance line shut-off valve 30.

The distribution arms 28 are connected to a main body component 31 thatprovides all the required internal cavities. The main body component 31is connected at one end to an oil separator assembly 32. As for thesuction header assembly 16, provision for more compressors are providedby a modular main body extension 33.

An oil separator assembly 32 is provided with required internals, aservice valve 34, and a non-return valve 35. The oil separator assembly32 also provides for connection to a refrigeration or air conditioningsystem via a pipe work adapter 36.

The main body component 31 is designed so that additional main bodycomponents can be added to further increase the size of the apparatus asrequired. This is effected by an end connection 37. Where no furtherextension is required to the apparatus, then a sealing end plate 38 isfitted. A similar part 39 is used at the end of the suction headerextension 16.

A filter assembly 40 provides a suction filter/dryer function. Thefilter assembly 40 is attached to the suction header assembly 16. Thefilter assembly 40 incorporates a service valve 41. Provision is alsomade for connection to the refrigeration or air conditioning system viaa pipe work adapter 42.

Pressure tapping points 43 are provided at convenient and usefullocations throughout the apparatus.

Referring now to FIG. 3, there is shown known conventionally constructedapparatus which exactly matches the functionality of the apparatus shownin FIGS. 1 and 2. Because of the methods of construction and otherissues involved known to a competent professional installer, the numberand position of the shut-off valves have been modified to achieve afunctional match with the apparatus shown in FIGS. 1 and 2.

FIG. 3 is similar to FIG. 1, which many of the same parts. In FIG. 3 itwill be noticed that there is an oil line 44 and gas balance lines 45.Because these are provided by discrete pipelines, typically in copper,two shut-off valves 46 are required. An oil reservoir 47 is required forthe apparatus shown in FIG. 3 as there is not enough volume in the oilfeed lines to accommodate the oil requirement of the system. Forsimplicity of illustration, an oil regulating system has not been shown,but one would be required.

In the apparatus show in FIG. 3, an oil regulating system has not beenshown for simplicity. Although the apparatus shown in FIG. 3 istheoretically possible with existing technology, the gas-balancing ofmore than three large compressors is not possible due to limitations ofcurrent known designs. In reality, for apparatus of the size shown inFIG. 3, an oil regulating system would be required. The oil regulatingsystem would in turn require extra parts and costs. The extra partswould in themselves provide an additional leak potential due to anincreased number of joints.

The disadvantages of the known apparatus shown in FIG. 3 can clearly beseen from FIG. 4. In FIG. 4, bold lines are used to indicate individualparts. The circuit diagram shown in FIG. 3 is included in FIG. 4 as adashed line 48.

FIG. 4 shows that there are some pipe fittings for T-joints 49 and rightangle bends 50. The apparatus shown in FIG. 4 is simplified and, inreality, the apparatus shown in FIG. 4 would require more fittings thanthose shown in order to run the pipe lines that are required. Time andeffort would be needed in order to bend pipe work to ensure a coherentsystem.

Where a pipe run ends, a blanking plate 51 is required to seal the pipe.A blanking plate 51 would be required for each pipe end. Because theparts of the apparatus are supplied separately, there is a requirementfor a plurality of joints to link these to the system.

Comparing FIG. 4 to FIG. 2, it is clear that the known conventionalapparatus shown in FIG. 4 requires far many more parts and joints thanthe apparatus according to the invention and shown in FIG. 2. In theapparatus shown in FIG. 2, there are 34 main joints between major parts,including blanking plates and access plates for the suction filter andoil reservoir float. There are 18 service valve seals, 5 non-returnvalve seals, 4 sight glass seals and 14 pressure tapping/drain points.The apparatus shown in FIG. 2 thus has 75 potential locations for aleak.

In the known apparatus shown in FIG. 4, there are 170 component joints(including end caps, copper pipe joints, joints to sight glass unit andaccess plates for the suction filter and reservoir float), 26 servicevalve seals, 5 non-return valve seals, 4 sight glass seals, and 14pressure tapping/drain points. The apparatus shown in FIG. 4 thus has219 potential locations for a leak.

From a comparison of FIGS. 2 and 4, it will be seen that the leakpotential of the apparatus of the present invention is nearly threetimes lower than for the known apparatus. In actual fact, a skilledperson producing the apparatus of FIGS. 2 and 4 would probably requiremore joints than mentioned above, which would put the leak potential ofthe present invention at more than three times lower than for a knownsystem.

It is to be appreciated that the embodiment of the invention describedabove with reference to the accompanying drawings has been given by wayof example only and that modifications may be effected. The combinationof multiple cavities and functions in the main body component orcomponents can be achieved by many beneficial configurations, and theapparatus shown in FIGS. 1 and 2 is of one embodiment only. Otherfunctionality may be provided in the main body component or components.

1. Apparatus for connecting together at least two compressors used inrefrigeration or air conditioning systems, which apparatus comprises asuction header, a discharge header, an oil header, oil return lines andan oil reservoir, which apparatus is characterised in that the suctionheader, the discharge header, the oil header, the oil return lines andthe oil reservoir are connected together in at least one main bodycomponent having an internal chamber, ports and valve cavities; and inthat the compressors are connectable to the main body component. 2.Apparatus according to claim 1 and including housings for all requiredservice, shut-off, control and regulating valves in suction, dischargeand oil pathways.
 3. Apparatus according to claim 1 and including aplurality of gauge and pressure relief points.
 4. Apparatus according toclaim 1 in which internal cavity sizes are large enough to cause areduced pressure drop between inlet and outlet sections of theapparatus.
 5. Apparatus according to claim 1 and including independentsuction accumulator means for each compressor.
 6. Apparatus according toclaim 1 and including an oil drain port and an oil sight glass. 7.Apparatus according to claim 1 and which is in modular form forconnecting the compressors together by extension modules.
 8. Apparatusaccording to claim 1 in which the low pressure oil reservoir is locatedat compressor sump level.
 9. Apparatus according to claim 1 andincluding a detachable oil separator.
 10. Apparatus according to claim 1wherein sufficient internal volume and flow area are provided so thatgas balancing of more than three large compressors is possible to ensureconsistent oil feed to each compressor without the need for an oilregulating system.
 11. Apparatus according to claim 1 and including abolt-on oil-feeder connector.
 12. Apparatus according to claim 1 inwhich oil feed and gas-balancing is combined in one cavity. 13.Apparatus according to claim 1 including a bolt-on suction filterassembly, the bolt-on suction filter assembly incorporating bypassvalves and service valves.
 14. Apparatus according to claim 1 andincluding liquid sub-cooling.
 15. Apparatus according to claim 9 andincluding a bolt-on oil separator, the bolt-oil separator being suchthat it is cast complete with integral bypass valves and service valves.